Unit for the regulation or control of a fluid pressure

ABSTRACT

A unit ( 10 ) for the regulation or control of a fluid pressure, having at least one housing section ( 13, 14 ) and a switching film ( 22 ) connected to the at least one housing section ( 13, 14 ) for switching at pressure differentials relative to an ambient pressure acting on the switching film ( 22 ), and for the regulation, release or blocking of a flow of the fluid between an inlet ( 28 ) and a discharge ( 30 ) for the fluid. The switching film ( 22 ) is made out of a polymer material having fluorine and carbon, in particular a thermoplastic having fluorine and carbon. In this arrangement, a hole cross-section ( 40 ) of the at least one housing section ( 13, 14 ) is closed off by the switching film ( 22 ).

TECHNICAL FIELD

The invention relates to a unit for the regulation or control of a fluidpressure, in particular for the pressure regulation of an internalcombustion engine and/or of the crankcase of the internal combustionengine of a motor vehicle and a method for fluid-tight connection of aswitching film to at least one housing section of the unit.

BACKGROUND

Pressure regulating valves are used, for example, in the breather linebetween crankcase and the intake manifold of an internal combustionengine. This involves not allowing the pressure or vacuum in thereceptacles to be vented to increase beyond a predetermined value.

In internal combustion engines, blow-by gases occur that are produced bycombustion gases in the cylinder getting past the cylinder piston intothe crankcase. These blow-by gases allow the pressure in the crankcaseto rise, whereby leaks and spillages of oil can be the result. In orderto prevent a pressure increase and to discharge these blow-by gases inan environmentally friendly manner, these are conducted from thecrankcase back into the air feeder line of the internal combustionengine. Furthermore, the specified negative pressure value should not besignificantly undershot, because otherwise undesired air can beerroneously sucked into the crankcase.

In the pressure regulating valves that are currently being used, anelement familiar to a person skilled in the art under the term“switching membrane” made from elastomer, commonly fluorosilicone rubberis generally employed. These switching membranes are very flexiblebecause of the specific properties of elastomers. Depending on theapplied pressure ratios, this switching membrane opens or closes anopening in the pressure regulating valve. The pressure ratio generallyresults from the pressure differential between the applied pressure in afirst chamber and the pressure prevailing in a second chamber of thepressure regulating valve. The pressure in the first chamber may forexample be the same as the atmospheric pressure. The switching membranemust react to low switching pressures on the order of 1 to 250 mbar.

Blow-by gases in an internal combustion engine are made up of unburnedfuel components, motor oil components and other pollutants resultingfrom the combustion. These gases attack many elastomer types, wherebydamages to the material properties can occur. The components made fromthese materials become brittle, porous and cracked. If the switchingfilms are damaged, the environmentally damaging blow-by gases passdirectly into the environment, because the system is no longer sealed.The switching membrane made from elastomer is generally executed as rollfilm, in order to realize a specific stroke of the switching membrane.The material in the roll region is also mechanically damaged through theunrolling motion by simultaneous contact with blow-by gases and can thusbe damaged.

The DE 26 29 621 A1 discloses a diaphragm valve having a switchingmembrane that is designed as a switching film clamped at its edgebetween the housing and the housing cover which is to be brought into asealing contact by a pressure member against a seating surface providedin the housing, wherein the switching membrane is made of a thinnerlayer of low elasticity, for example from PTFE, facing towards thehousing interior that is resistant to aggressive through-flow media, andan additional, thicker layer made of elastomeric material. Diaphragmvalves of this type are primarily used where a high chemical resistanceof the materials coming into contact with the through-flow medium isrequired. Because elastomeric materials do not meet this requirement butthe chemically resistant materials such as PTFE do not possess theelasticity necessary for a proper function, films comprising two layersare used. The contact pressure that is applied by the pressure membervia the thick, rubber-like layer is transmitted as evenly as possibleonto the sealing surface of the switching film that works together withthe seating surface in the housing. In this arrangement, relativelylarge switching pressures of several bar are exerted on the switchingmembrane for closing the two-layered switching membrane via a pressurespindle that is connected to a hand wheel in order to ensure thenecessary sealing function by the stiff PTFE layer.

SUMMARY OF THE INVENTION

It is an object of the invention to create a unit for switching at lowpressure differentials that achieves a high operational life inoperation in an internal combustion engine with aggressive media, inparticular from so-called blow-by gases

It is an additional object of the invention to create a method forfluid-tight connection of a switchable closing element to the unit, thatachieves a high operational life during operation in an internalcombustion engine having aggressive media, in particular from solocalled blow-by gases.

The aforementioned object is achieved according to one aspect of theinvention by a unit for regulation or control of a fluid pressure and ofa switching film connected to at least one housing section, wherein theswitching film is formed from a polymer film from a polymer materialhaving fluorine and carbon and wherein a hole cross-section of the atleast one housing section is closed off by the switching film. Theswitching film having fluorine and carbon can be formed in particular bya film from thermoplastic having fluorine and carbon.

According to another aspect of the invention, the additional object isachieved by a method for fluid-tight connection of a switching film toat least one housing section or a unit, wherein the switching film isconnected to the at least one housing section by the at least partialmelting the joining region and/or the mating surface.

Favorable embodiments and advantages of the invention are disclosed inthe further claims, the description and the drawings.

A unit is proposed for the regulation or control of a fluid pressure,having at least one housing section and a switching film connected tothe at least one housing section for switching at pressure differentialsof 1 to 250 mbar, preferably from 1 to 100 mbar, relative to an ambientpressure acting on the switching film, and for the regulation, releaseor blocking of a flow of the fluid between an inlet and a discharge forthe fluid, wherein the switching film is made out of a polymer materialhaving fluorine and carbon, in particular thermoplastic having fluorineand carbon, and wherein a hole cross-section of the at least one housingsection is closed off by the switching film.

The unit does not only serve to release or shut off a through-flow, butregulates between the two switching states “release” or “shut off” by acontinuous alteration of the through-flow cross-section as a function ofthe pressure differential on the through-flow of fluid between the inletand the discharge. In this manner, the through-flow can be restricted.

A polymer film having fluorine and carbon, in particular a thermoplasticfilm having fluorine and carbon, is chemically resistant and can switchmany switching cycles of the film valve. The long-term stability of theunit is improved. In particular, the polymer film having fluorine andcarbon can be PTFE (polytetrafluorethylene). Alternatively, the polymerhaving fluorine and carbon can be made of a PTFE as the base material,which has admixtures, in particular an admixture of glass fiber, glassspheres, graphite and/or carbon fibers, in particular having aproportion of the admixed substances of up to 60%; similarly, thepolymer having fluorine and carbon can be a thermoplasticallyprocessable PTFE, which is processable in a spraying process, inparticular.

Preferably, the switching film is at most 0.5 mm thick, preferably atmost 0.3 mm, particularly preferably at most 0.2 mm thick. The switchingfilm can have a diameter between 40 mm and 100 mm, preferably between 50mm and 80 mm. It is possible that with correspondingly large diameterssomewhat higher thickness of the switching film in the region of over0.5 mm, for example at most 0.5 mm to 1 mm, can be realized.

A conventional switching membrane made from elastomer of a conventionalunit for pressure regulation of an internal combustion engine and/or thepressure regulation of the crankcase of an internal combustion engine isreplaced here by a switching film made from the polymer having fluorineand carbon, in particular a thermoplastic having fluorine and carbon. Apolymer material having fluorine and carbon such as PTFE can, forexample, be manufactured in a sintering process and then mechanicallyprocessed. Such a switching film in its normal form is very stiff andactually not appropriate for flexible components. PTFE has anoutstanding chemical resistance and can be used in a very broad range oftemperatures, wherein the modulus of elasticity is very sharplyincreased at low temperatures compared to elastomeric materials. Forthis reason, PTFE is not appropriate for an application as switchingfilm in the temperature range required for automotive applications in aninternal combustion engine of typically −40/° C. to +150° C. Thisdisadvantage is avoided in the unit according to the invention by virtueof an advantageous geometry and optionally by an extremely thin wallthickness of the switching film made from the polymer having fluorineand carbon, in particular a thermoplastic having fluorine and carbon.

By reducing the wall thickness of the material in the switching film inan intentionally movable range of a few tenths of a millimeter, whereinthe intentionally fixed thickness range as well as the clamping regionof the material can also be executed thicker, and a specially developedgeometry of the switching film without roll region, as it isconventionally used in prior art, the stiff material is formed into ashape in which it has the necessary flexibility, but neverthelessfulfills the mechanical requirements with respect to crack formation,strain and fatigue strength under reversed bending stresses. By virtueof the special geometry, roll motion no longer takes place, rather abending motion can be realized having a radius change that can beaccomplished with low strain or even practically no strain of thematerial and with which a lifting motion of the switching film for theunit according to the invention can be implemented.

The switching film can have a plate-like flat body, in particular formedas plate-shaped flat body, having a bending region surrounding a centralsealing region, wherein the bending region moves the sealing region inan axial direction with respect to a valve seat, meaning in thedirection normal to the flat body, onto the valve seat or away from thevalve seat during switching of the switching film by alow-strain—meaning practically strain-free for practical application, inparticular strain-free—bending motion. Because the switching film inthis embodiment can flex not only in a small surface region, but broadlybecause of the plate-like shape, individual regions of the switchingfilm are hardly or practically not at all strained. The bending motionis thus executed across a large region of the switching film—and,consequently, with little elastic deformation—in the form of a curvaturechange with low strain, for example less than 10%.

The sealing region of the switching film can interrupt the through-flowof the fluid between the inlet and the discharge. The switching filmcan, for example, be located with its sealing region against a seal seatin order to interrupt the through-flow.

For this purpose, the switching film can be movable between itsrespective maximum positions in the opened and closed state byapplication of atmospheric pressure as control pressure on one side ofthe switching film. Advantageously, the switching film can beself-regulating and the switching film can be closed indirectly via apressure differential between atmospheric pressure in the one chamber ofthe unit and an operating pressure of the other chamber of the unit. Theoperating pressure can, for example, be a pressure in a crankcase of aninternal combustion engine.

Advantageously, the switching film can alternatively be movable betweenits respective maximum positions in the opened and closed state, if onone side of the switching film a control pressure is applied that doesnot equal an atmospheric pressure and/or a mechanical actuating means isprovided to switch the switching film.

Via a spring element, which is supported against the at least onehousing section, a force is applied to the switching film in order to beable to adjust the control response of the unit. For this purpose, thedischarge can have a valve seat arranged at an end in the housingsection, which is sealable by the sealing region of the switching film,whereby a discharge of fluid from the inlet to the discharge can beregulated. The spring element in this arrangement exerts the appropriatecounterforce on the switching film to achieve a control response of theunit in the desired pressure region. The side of the switching filmfacing away from the fluid to be regulated is generally supplied herewith atmospheric pressure.

According to the invention, a hole cross-section of the at least onehousing section of the unit is closed off by an operating region of theswitching film. In this manner the throughflow of the unit can beregulated, released, shut off or limited. An edge region surrounding theoperating region of the switching film allows a fluid-tight connectionof the switching film made from a polymer having fluorine and carbon, inparticular a thermoplastic having fluorine and carbon, against thehousing of the unit, which can be advantageously made from plastic, forexample, glass-fiber reinforced polyamide (PA), and represents anadditional great advantage over the prior art, in which the impermeableor closed membranes have no claim to tightness, rather, they are onlyinterlockingly connected to the housing. By virtue of the fluid-tightconnection, a region of the unit is advantageously guaranteed to besealed as fluid-tight, for example as a pressure regulation valve,because the switching film can in each case seal a housing sectionfluid-tight by being fixedly connected to the housing section, as wellas sealing of the interior spaces of two housing sections against eachother, if the first housing section is sealed with a second housingsection, such as with a housing cover.

According to one advantageous embodiment, at least one circumferentialmating surface can be provided situated radially to the outside on theat least one housing section at which the switching film is connected,in particular fixedly connected, in particular fixedly and fluid-tightlyconnected to the at least one housing section. By the fixed connectionof the switching film to the outer radially circumferential matingsurface, the central inner region of the switching film can move freelyas a whole in the axial direction and as a sealing region of theswitching film can thus exercise the actual switching function of theunit, for example as pressure regulation valve. Through the fluid-tightconnection of the switching film against at least one housing section,it can also be effectively prevented that possible outgassing of thematerial into the environment.

According to one advantageous embodiment, a radially outwardly situatedjoining region of the switching film can be connected to the at leastone housing section by the at least partial melting of the joiningregion of the switching film and/or the mating surface of the housingsection, in particular integrally and/or interlockingly. An integraland/or interlocking connection of the switching film by the melting ofthe material, for example through welding, with the mating surface ofthe housing section, which can ensure the fluid-tight sealing of thehole cross-section of the housing section as well as the fixed anddurable connection of the switching film for a safe function during theoperation of the unit. The melting allows for one of the joiningmembers, the joining region of the switching film or the mating surfaceof the housing section, to melt and to at least partially connect withthe respective other joining member. Alternatively, it is also possiblethat both joining members are melted and that the melted materials mixand thus are firmly connected when setting. It is furthermore possiblethat only the housing section is melted and the thus melted material ofthe housing section connects to the switching film. This way, thematerials do not mix directly. This way, however, a partially integral,partially interlocking connection can be achieved. In particular anintegral connection can be achieved at least in one of the top materiallayers by activating at least one surface of the switching film.

According to an advantageous embodiment, at least one circumferentialgroove can be provided in the mating surface of the at least one housingsection to accommodate melted material from the joining region and/orthe mating surface, whereby in particular one circumferential groove canbe radially situated within the mating surface of the at least onehousing section and one circumferential groove radially situated outsidethe mating surface of the at least one housing section to accommodatemelted material from the joining region and/or the mating surface. Themelted and excess material can in this manner be effectivelyaccommodated by the groove and thus distributed in the groove in atargeted manner during the application and pressing of the switchingfilm against the housing section, so that the joining region of theswitching film and the mating surface of the housing section adheredirectly against one another, thereby creating a fluid-tight and durableconnection. This way, the excess melted material can, in particular,flow from both sides of the joint and be distributed in the grooves sothat the joining region of the switching film and the mating surface ofthe housing section can directly bond with each other.

For preparation of the melting, it can be advantageous to prepare thesurface of the switching film accordingly in that region where theswitching film will bond with the housing section in order to change thesurface tension. Such an activation can thus expediently include one ormore methods such as etching, plasma treatment, mechanical roughening,stamping, perforating or similar, appropriate methods. This may improvethe connection between the joining members. In particular, it isadvantageous to subject a surface of the switching film that is exposedto the fluid, such as is the case in a first chamber of the firsthousing section, to a treatment by activation.

According to one advantageous embodiment, the mating surface of the atleast one housing section can be formed to be self-adjusting in alongitudinal direction. In particular, the mating surface can be formedconically or curved upwards or downwards or corrugated.

By virtue of the self-adjusting mating surface, a particularly goodconnection of a different housing section as well as of the switchingfilm can be ensured with automatic centering of the first housingsection or of the switching film before and during the process of theconnection.

According to one advantageous embodiment, at least one radiallycircumferential groove can be provided radially inside the matingsurface of the at least one housing section and radially delimited onthe inside by an edge for supporting the switching film when there areaxial movements transverse to the hole cross-section, wherein inparticular two axial opposing and/or radially offset grooves can beprovided with an edge, in particular a raised lip. A raised lip on theedge advantageously supports dynamic movements of the switching filmwith its working region during the execution of the function in thepressure valve and simultaneously achieves a protection against damageby the motion of the switching film. The groove with the raised lip canthus be expediently configured in such a way that it accommodates thewelding beads in such a way that, after the welding, no welding beadsremain in the pending region of the switching film to avoid any damageto the same during operation. The switching film is thereby alwayslocated on at least one edge, preferably however at two edgessimultaneously during its switching motion. In order to prevent a damageto the switching film during the joining process such as, for example,by an unacceptable compression of the switching film by the edges, theedges can be arranged radially offset. A realization of a connection isthus easier, in that the switching film is located on two edgessimultaneously. A movement on the boundary surface to a welding bead oran edge can then be prevented. The edge can be optimized for the filmmotion so that the switching film in operation is protected againstdamage by the edge. It is also possible to apply a prestress of theswitching film via these edges.

According to one advantageous embodiment, a housing can be provided withthe first housing section and a second housing section, and the firstchamber can be separated fluid-tight from a second chamber by theswitching film. The second chamber of the unit can thus be supplied withan atmospheric pressure. For an effective control response of the unit,the switching film should be able to move as freely as possible, forwhich reason the second chamber, which is separated by the functionalregion of the switching film from the first chamber, in which the fluidto be controlled is located, is expediently in connection with theenvironmental region, meaning with the atmospheric pressure.

According to one advantageous embodiment, at least one housing sectioncan be formed radially outside the mating surface for closure of the atleast one housing section with the second housing sections through atleast partially melting the edge. Advantageously, at least one housingsection can thus be formed radially outside the mating surface forclosure of the hole cross-section through melting with the switchingfilm. Additionally, the housing section, in which the hole cross-sectionis closed fluid-tight by the switching film, can in this way be firmlywelded to another housing section, for example a cover, or the housingsection can be welded to a different component. In this manner, afurther fluid-tight sealing of the unit for safe operation, for exampleas a pressure regulating valve, can be achieved. The mating surface forthe welding can thus expediently be designed so that the weld beads fromthe welding process do not adversely affect the connection of thehousing section.

According to one advantageous embodiment, the polymer material havingfluorine and carbon is polytetrafluoroethylene orpolytetrafluoroethylene with admixtures or thermoplastically processablepolytetrafluoroethylene.

According to a different aspect of the invention, a method for thefluid-tight connection of a switching film to at least one housingsection of a housing of a unit is proposed, wherein the switching filmis formed from a polymer material having fluorine and carbon, inparticular a thermoplastic having fluorine and carbon, and wherein ajoining region of the switching film situated radially to the outsidethat is connected, and in particular firmly connected, in the area of atleast one mating surface to the at least one housing section by at leastpartially melting the joining region and/or the mating surface. Thismethod comprises an application and pressing of the joining region ofthe switching film against the mating surface of the at least onehousing section, followed by an at least partial melting of the joiningregion and/or the mating surface. After the compressing the switchingfilm with the housing section and the melting and solidifying of themelted material, a durable and fluid-tight connection of the switchingfilm at the housing section and thus a fluid-tight sealing of the holecross-section of the housing section can thus be achieved.

According to one advantageous embodiment, the joining region of theswitching film is pretreated by at least one of the methods, etching,plasma treatment, mechanical grinding, embossing or perforation. Forpretreatment of the melting, it is advantageous to accordingly pretreatand activate the surface of the switching film in the region where it isconnected with the housing section, which can be achieved with one ofthe procedures mentioned. In this way the surface tension can bechanged, whereby the process of the thermal fusion can be essentiallyimproved.

According to one advantageous embodiment, the melting of the joiningregion of the switching film and/or the melting of the mating surface ofthe housing section can be achieved by means of at least one of themethods of melting, ultrasound melting, mirror-imaged welding, laserwelding, thermal fusion. These welding methods are suitable inparticular for creating a permanent bond between joining members fromplastic and can be used for that in a proven manner.

According to one advantageous embodiment, a second housing section canadvantageously be placed on the switching film after the placement ofthe switching film on the at least one first housing section with thejoining region over the mating surface, and the housing is thus formed.At the same time, the second housing section can also be expedientlyconnected to the switching film and/or to the first housing section bymelting the material. Alternatively, it is also conceivable to radiallyconnect the two housing sections, which can be formed from, for example,glass-fiber reinforced polyamide (PA), outside the switching film, inparticular by welding.

According to an advantageous embodiment, the joining region of theswitching film can be compressed when the housing is sealed in theregion of the mating surface. In this way, the fluid-tight connectioncan also be favorably improved.

Advantageously, the switching film can be axially supported by at leastone groove running radially inside the mating surface in the at leastone housing section, which is radially delimited inside by a lip, inparticular a raised lip, for supporting the switching film during axialmovements transverse to its cross-sectional area. In this way, dynamicmovements of the switching film during the execution of the function inthe pressure regulating valve can be advantageously supported and, atthe same time, a protection against damage by the movement of theswitching film can be achieved. The groove with the raised lip is thusexpediently configured in such a way that it accommodates the weldingbead so that, after the melting process, no residues from a welding beadremain in the pending region of the switching film to avoid any damageto the same during operation. The switching film is thereby alwayslocated on at least one edge, preferably however at two edgessimultaneously during its switching motion. In order to prevent a damageto the switching film during the joining process such as, for example,by an unacceptable compression of the switching film by the edges, theedges can be arranged radially offset. A realization of a connection isthus easier, in that the switching film is located on two edgessimultaneously. A movement on the boundary surface to a welding bead oran edge can then be prevented. The edge can be optimized for the filmmovement so that the switching film is protected against damages by theedge during operating mode.

Advantageously, the switching film can also be axially supported by twogrooves arranged in the housing with an edge, which are arrangedopposite each other or radially displaced relative to each other. Inthis further embodiment, the edges of the housing section can bemutually shifted so that the switching film is not crimped in thisregion during the joining process. It is also possible to adjust thepretension of the switching film via these edges.

Furthermore, the housing can also be sealed to a radial outercircumference in an expedient manner after connection of the switchingfilm to the at least one housing section by means of at least partiallymelting a raised lip of at least one housing section radially arrangedoutside of the mating surface. Additionally, the housing section, inwhich the hole cross-section is closed fluid-tight by the switchingfilm, can in this way be firmly welded to another housing section, forexample a cover, or the housing section can be welded to a differentcomponent. In this manner, a further fluid-tight sealing of the unit forsafe operation, for example as a pressure regulating valve, can beachieved. The mating surface for the welding can thus expediently bedesigned so that the weld beads from the welding process do notadversely affect the connection of the housing section and theconnection of the switching film with the housing components.

According to a further aspect of the invention, the unit according tothe invention is used for pressure regulation of an internal combustionengine and/or for pressure regulation of a crankcase of an internalcombustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages arise from the following drawing description.Embodiments of the invention are illustrated in the drawings. Thedrawings, the description and the claims contain numerous features incombination. A person skilled in the art will also expediently considerthe features on an individual basis and combine them into otherappropriate combinations.

Shown by way of example are:

FIG. 1 a unit having a switching film made from a polymer with fluorineand carbon according to an exemplary embodiment of the invention in asectional view;

FIG. 2 a unit having a switching film according to an additionalexemplary embodiment of the invention in a sectional view;

FIG. 3 a unit having a switching film that is mounted but not yetconnected according to a next exemplary embodiment of the invention in asectional view;

FIG. 4 the unit from FIG. 3 with connected switching film and weldedhousing in a sectional view;

FIG. 5 a unit having a switching film that is mounted but not yetconnected according to a next exemplary embodiment of the invention in asectional view;

FIG. 6 the unit from FIG. 5 with connected switching film and weldedhousing in a sectional view;

FIG. 7 a simplified detail of a version of the unit's joining regionfrom FIG. 3 with just one groove and without a second housing section ina sectional view;

FIG. 8 a detail of the unit's joining region from FIG. 7 after theconnection process in a sectional view;

FIG. 9 a detail of the unit's joining region from FIG. 3 in a sectionalview;

FIG. 10 a detail of the unit's joining region from FIG. 9 after theconnection process in a sectional view;

FIG. 11 a detail of the unit's joining region from FIG. 5 in a sectionalview; and

FIG. 12 a detail of the unit's joining region from FIG. 6 after theconnection process in a sectional view.

DETAILED DESCRIPTION

The same or similar components in the figures are referenced with samereference characters. The figures merely show examples and are notintended to be restrictive.

FIG. 1 shows a sectional view of a unit 10 for the regulation or controlof a fluid pressure using a switching film 22 made from a polymer havingfluorine and carbon according to an exemplary embodiment of theinvention. The polymer material having fluorine and carbon is thuspolytetrafluoroethylene or polytetrafluoroethylene with admixtures orthermoplastically processable polytetrafluoroethylene particularly in aspraying process. The unit 10 serves for regulation or control of afluid pressure, in particular for application for pressure regulation ofan internal combustion engine and/or for the pressure regulation of acrankcase of an internal combustion engine. The unit 10 has a housing 12having a first housing section 13 and a second housing section 14, thehousing cover, wherein the first housing section 13 has an inlet 28 anda discharge 30 for the fluid. The switching film 22 is formed from apolymer film having fluorine and carbon, for example PTFE, and isclamped with a joining region 42 between first housing section 13 andthe second housing section 14.

The hole cross-section 40 of the two housing sections 13, 14 is sealedby the switching film 22 with its functional region. Two circumferentialmating surfaces 50, 52 are provided situated radially to the outside onthe two housing sections 13, 14, at which the switching film 22 isconnected fluid-tight to the two housing sections 13, 14. In theexemplary embodiment shown, a joining region 42 of the switching film 22is thus, in particular, integrally and/or interlockingly connected tothe two housing sections 13, 14 by means of an at least partial meltingof the joining region 42 of the switching film 22 and/or the matingsurface 50, 52 of the housing section 13, 14. In the exemplaryembodiments in FIGS. 1 and 2, the melted area 44 is shown in a diagramby means of welding beads 48. The details of the melted area 44 withgrooves 46, 64 and welding beads 48 are shown in FIGS. 4, 6, 8, 10, and12.

The switching film 22 separates a first chamber 36 of the unit 10 from asecond chamber 38 in a fluid-tight manner. There is a pressuredifferential between the first chamber 36 and the second chamber 38,wherein the second chamber 38 is connected (not depicted) to thesurrounding space, meaning to the atmosphere. The switching film 22 canbe moved with pressure differences of 1 to 250 mbar, preferably from 1to 100 mbar, and serves to release or shut off a through-flow of thefluid between the inlet 28 and the discharge 30. The inlet 28 of theunit 10 is fluidically connected during use to, for example, thecrankcase of an internal combustion engine, while the discharge 30 isfluidically connected to the breather line. The switching film 22 has aplate-like flat body 16 having a corrugated bending region 18surrounding a central sealing region 24. The bending region 18 movesduring switching of the switching film 22 by a low-strain, in particularstrain-free bending motion of the sealing region 24 with respect to avalve seat 32 in an axial direction L toward the valve seat 32 or awayfrom the valve seat 32. For this, the switching film 22 has at least inthe bending region 18 a thickness of at most 0.5 mm, preferably of atmost 0.3 mm, most preferably of at most 0.2 mm. The diameter of theswitching film 22 can thus be between 40 mm and 100 mm, preferablybetween 50 mm and 80 mm.

The bending region 18 extends in a wave-like manner in radial directionaround sealing region 24, wherein a recess on a flat side corresponds toan elevation on the other flat side of the switching film 22. Thesealing region 24 seals the valve seat 32 if it is located on the valveseat 32. A spring element 26 is provided that is supported at the firsthousing section 13 which exerts a force on the sealing region 24 of theswitching film 22. The spring element 26 is supported here by anannularly formed plate 34 at the sealing region 24. The sealing region24 is formed as a bowl-shaped projection 20 of the switching film 22,wherein the plate 34 in the form of a support ring annularly enclosesthis projection. The spring element 26 can alternatively engage theswitching film 22 without plate 34 and thus be sprayed on its end facethat is turned towards the projection 20 for protection of the switchingfilm 22, so that the encapsulation can replace the plate 34.

A groove 54, 56 running radially is provided inside the mating surface50, 52 of each of the two housing sections 13, 14, which is delimitedradially inside by an edge 58, 60 for supporting the switching film 22during axial movements transverse to the hole cross-section 40. The twogrooves 54, 56 are located axially opposite one another. Because theswitching film 22 is located on the rounded edges 58, 60 and is clampedbetween them, the switching film 22 is protected against excessive wearand damages from sharp edges resulting from axial movements of itsworking region because of the regulating function of the unit 10.

FIG. 2 shows in a cross-sectional view a unit 10 having a switching film22 according to an additional exemplary embodiment of the invention. Thebasic design of the unit 10 essentially corresponds to the exemplaryembodiment in FIG. 1. The mating surfaces 50, 52 of the two housingsections 13, 14, however, are formed conically in the longitudinaldirection L. In this manner, the switching film 22 can advantageously becentered during the joining of the switching film 22 at the firsthousing section 13 and during assembly of the housing 12 by placement ofthe second housing section 14. The grooves 54, 56 with their edges 58,60—in contrast to the embodiment in FIG. 1 where they are arrangedaxially opposed—are arranged in this case radially displaced, which canalso be beneficial for the support of the switching film 22 during theaxial movement of the switching film 22.

FIG. 3 shows a unit 10 having a bonded switching film 22 prior to theconnection process according to a next exemplary embodiment of theinvention in a sectional view. The spring element 26 was left out toprovide greater clarity. FIGS. 7 and 9 both show an detail of thehousing 12 of unit 10 from FIG. 3 with the joining region 42 or,respectively, a simplified detail of the housing 12. FIG. 7 is shown asanother embodiment of the connection of a version without the groove 64in the first housing section 13, wherein only a groove 46 and no secondhousing section is provided above the switching film 22. In analternative embodiment, a second housing section can be provided whichcovers the switching film 22.

The sectional view of unit 10 in FIG. 3 shows that a circumferentialgroove 46 is provided in the mating surface 50, of the first housingsection 13 to accommodate melted material from the joining region 42and/or the mating surface 50. In comparison with the two exemplaryembodiments in FIGS. 1 and 2, the unit 10 in FIG. 3 does not have anygrooves 54, 56. The switching film 22 is mounted between the two housingsections 13, 14. Lips 58, 60 with a rolling radius to relieve theswitching film 22 are provided.

A joining region 42 situated radially outside the switching film 22 isthus firmly connected to the first housing section 13 in the area of themating surface 50 means of an at least partial melting of the joiningregion 42 and/or the mating surface 50 by placing and pressing thejoining region 42 of the switching film 22 against the mating surface 50of the first housing section 13 and at least partially melting thejoining region 42 and/or the mating surface 50. Here, the melting of thejoining region 42 and/or the mating surface 50 can be achieved by meansof at least one of the methods of melting, ultrasound melting,mirror-imaged welding, laser welding, thermal fusion. Advantageously,the switching film 22 in this arrangement, at least in the region of thejoining region 42, has an activated surface with altered surface tensionin order to achieve a good connection, wherein the joining region 42 isprepared, for example, by one of the methods, etching, plasma treatment,mechanical roughening, embossing or perforation. After the seating ofthe switching film 22 on the at least first housing section 13 with thejoining region 42 over the mating surface 50, a second housing section14 is seated on the switching film 22 and thus forms the housing 12. Thejoining region 42 of the switching film 22 is compressed during thesealing of the housing 12 in the region of the mating surfaces 50, 52.

FIG. 4 shows the unit 10 from FIG. 3 with the bonded switching film 22and the welded housing 12. FIGS. 8 and 10 both show a simplified detailof the housing 12 of unit 10 from FIG. 4 with the joining region 42 or,respectively, a detail of the joining region 42. FIG. 8 illustrates asanother embodiment of the connection of a version without the groove 64in the first housing section 13.

The housing 12 is sealed to a radial outer circumference in an expedientmanner after connection of the switching film 22 to housing section 13by means of at least partially melting a raised lip 66 of the housingsection 13 radially arranged outside of the mating surface 50. To thispurpose, the housing section 13 formed radially outside the mountingsurface 50 for closure of the hole cross-section 40 through welding. Tothis purpose, the first housing section 13 comprises the circumferentialgrooves 46, 64 whose purpose it is to accommodate a welding bead 48created during the welding of the housing 12 which is primarily formedfrom plastic, so that the two mating surfaces 50, 52 of the two housingsections 13, 14 are positioned directly on top of the switching film 22after the joining process.

Comparing the details shown in FIGS. 7 and 9 with the details shown inFIGS. 8 and 10, it becomes clear that the two housing sections 13, 14(FIGS. 9 and 10) are kept at a distance from each by the circumferentiallip 66 of the first housing section 13 other directly after theapplication of the switching film 22 and placement of the second housingsection 14, which does not disappear until after the two housingsections 13, 14 are welded together by the partial melting of thematerial on the mating surface 50 as well as the raised lip 66 of thehousing section 13, so that this way the two housing sections 13, 14 liedirectly on top of the switching film 22 and the switching film 22 ispressed between them in a fluid-tight manner.

FIGS. 5 and 6 shows a unit 10 with a switching film 22 according toanother exemplary embodiment of the invention in a sectional view,wherein the switching film 22 in FIG. 6 is firmly connected with thesecond housing section 4, which is formed as a lid. The arrangement ofthe grooves 46, 64 is formed laterally inversed to the embodiment shownin FIGS. 3 and 4 in the second housing section 14. Details about theconnection of the switching film 22 with the second housing section 14as well as the connection of the second housing sections 13, 14 areshown in FIGS. 11 and 12. The joining region 42 of the switching film 22is thus integrally and/or interlockingly connected to the two housingsections 14 by means of a melting of the joining region 42 and/or themating surface 52 of the housing section 14. The thus created weldingbeads 48 can be accommodated in the grooves 46, 64. The two housingsections 13, 14 are integrally connected by the melting of the raisedlip 66. By melting the material in the welding beads 48, the two housingparts 13, 14 lie directly on top of the switching film 22 at the matingsurfaces 50, 52 after the melting of the material and thereby furthercompress the switching film 22.

What is claimed is:
 1. A regulation unit for the regulation or controlof a fluid pressure, comprising: a regulation housing having: at leastone housing section; a fluid inlet port; a fluid discharge port; aswitching film connected to the at least one housing section and adaptedto switch at pressure differentials of 1 to 250 mbar relative to anambient pressure acting on the switching film; wherein the switchingfilm is adapted for regulation, release or blocking of a flow of thefluid between the inlet port and the fluid discharge port; wherein theswitching film is made out of a thermoplastic or a polymer materialhaving fluorine and carbon, wherein a first housing section of the atleast one housing section has a first chamber, the first housing sectionhaving a hole though which the first chamber opens to an exterior of thefirst housing section, the hole having a hole cross-section; wherein thehole cross-section of the at least one housing section is closed off bythe switching film.
 2. The regulation unit according to claim 1, whereinat least one circumferential mating surface situated radially to theoutside and radially surrounding the hole cross-section; wherein theswitching film is fixedly and fluid-tightly connected to the at leastone housing section and closing off the hole cross-section.
 3. Theregulation unit according to claim 2, wherein the switching film has ajoining region positioned radially to the outside of the switching film;wherein the at least one circumferential mating surface of the at leastone housing section is partially melted onto the joining region of theswitching film, integrally connecting the at least one circumferentialmating surface to the joining region.
 4. The regulation unit accordingto claim 2, wherein the at least one circumferential mating surface hasat least one circumferential groove formed therein; wherein the at leastone circumferential groove is adapted to receive melted material fromthe joining region and/or the at least one circumferential matingsurface; wherein the melted material is received into the at least onecircumferential groove.
 5. The regulation unit according to claim 2,wherein the at least one circumferential mating surface is formed in alongitudinal direction (L) traverse to a plane defined by the joiningregion of the switching film; wherein the at least one circumferentialmating surface of the at least one housing section is formed conically,curved or undulated such that the at least one circumferential matingsurface is self-adjust for mating.
 6. The regulation unit according toclaim 2, wherein the least one circumferential groove is radiallydelimited on the inside by an edge for supporting the switching filmwhen there are axial movements of the switching film transverse to thehole cross-section; wherein the edge is provided radially inside the atleast one circumferential mating surface of the at least one housingsection; wherein two axial opposing and/or radially offset grooves areprovided with the edge.
 7. The regulation unit according to claim 4,wherein the at least one housing section is two housing sections;wherein each of the two housing section has the circumferential matingsurface, the circumferential mating surfaces adapted to align formating, the circumferential mating surface having the at least onecircumferential groove formed therein; wherein the at least onecircumferential groove of each of the two housing sections are arrangedaxially opposite each other and/or radially offset when the regulationhousing is closed. the two housing sections are the first housingsection and a second housing section; wherein the second housing sectionhas a second chamber; wherein the first chamber is separated from thesecond chamber in a fluid-tight manner by the switching film.
 8. Theregulation unit according to claim 7, wherein at least one housingsection comprises a circumferential raised lip radially outside thecircumferential mating surface for closure of the first housing sectionwith the second housing section by at least partially melting of theraised lip.
 9. The regulation unit according to claim 2, wherein thematerial of the switching film comprises: polytetrafluoroethylene, orpolytetrafluoroethylene with admixtures, or thermoplasticallyprocessable polytetrafluoroethylene.
 10. A method of forming afluid-tight connection of a switching film onto at least one housingsection of a regulation housing of a regulation unit according to claim1, comprising the steps of: providing a switching film formed from athermoplastic material having fluorine and carbon, the switching filmhaving a joining region arranged radially to an outer side of theswitching film; providing a first housing section having a firstchamber, the first chamber surrounded by at least one circumferentialgroove formed into a mating surface of the first housing section;providing a second housing section having a second chamber, the secondchamber surrounded by at least one circumferential groove formed into amating surface of the second housing section; incorporating a foammaterial into the at least one circumferential groove of the firsthousing section; placing the switching film onto the first housingsection having the foam material with the joining region arranged at thecircumferential mating surface of the first housing section; pressingthe joining region of the switching film against the circumferentialmating surface of the first housing section; at least partially meltingthe joining region and/or the mating surface to fixedly connect thejoining region of the switching film onto the circumferential matingsurface of the first housing section.
 11. The method according to claim10, wherein prior to the step of placing the switching film, the methodfurther comprises: pretreating the joining region by at least one of themethods: etching, plasma treatment, mechanical grinding, embossing orperforation.
 12. The method according to claim 10, wherein the at leastpartially melting step is practiced by any of: ultrasound melting, ormirror-imaged welding, or laser welding, or thermal fusion.
 13. Themethod according to claim 10, wherein after the step of at leastpartially melting, the method further comprises: placing the secondhousing section onto the joining region of the switching film; pressingthe joining region of the switching film against the circumferentialmating surface of the second housing section; at least partially meltingthe joining region and/or the mating surface of the second housingsection to fixedly connect the joining region of the switching film ontothe circumferential mating surface of the second housing section. 14.The method according to claim 13, wherein the joining region of theswitching film is compressed during the pressing steps of claims 10 and13, the sealing of the regulation housing (12) in the region of thecircumferential mating surface.